Early reports in the fungus Ustilago maydis suggest that the amphipathic fungicide dodine disrupts the fungal plasma membrane (PM), thereby killing this corn smut pathogen. However, a recent study in the wheat pathogen Zymoseptoria tritici does not support such mode of action (MoA). Instead, dodine inhibits mitochondrial ATP-synthesis, both in Z. tritici and U. maydis. This casts doubt on an fungicidal activity of dodine at the PM. Here, we use a cell biological approach and investigate further the effect of dodine on the plasma membrane in both fungi. We show that dodine indeed breaks the integrity of the PM in U. maydis, indicated by a concentration-dependent cell depolarization. In addition, the fungicide reduces PM fluidity and arrests endocytosis by inhibiting the internalization of endocytic vesicles at the PM. This is likely due to impaired recruitment of the actin-crosslinker fimbrin to endocytic actin patches. However, quantitative data reveal that the effect on mitochondria represents the primary MoA in U. maydis. None of these plasma membrane-associated effects were found in dodine-treated Z. tritici cells. Thus, the physiological effect of an anti-fungal chemistry can differ between pathogens. This merits consideration when characterizing a given fungicide.

对玉米黑粉菌真菌的早期报道表明，两亲性杀菌剂多丁会破坏真菌质膜 (PM)，从而杀死这种玉米黑穗病病原体。然而，最近对小麦病原体小麦发酵壳孢菌的一项研究并不支持这种作用模式（MoA）。相反，多碘会抑制小麦和玉米中的线粒体 ATP 合成。这使人们对多多定在 PM 上的杀菌活性产生了怀疑。在这里，我们使用细胞生物学方法，进一步研究多多定对两种真菌质膜的影响。我们表明，多果碱确实破坏了玉米中 PM 的完整性，这由浓度依赖性细胞去极化表明。此外，该杀菌剂通过抑制 PM 内吞囊泡的内化来降低 PM 流动性并阻止内吞作用。这可能是由于肌动蛋白交联剂纤维蛋白向内吞肌动蛋白斑块的募集受损。然而，定量数据表明，对线粒体的影响代表了玉米中的主要 MoA。在多碘处理的小麦小麦细胞中没有发现这些与质膜相关的效应。因此，抗真菌化学物质的生理作用在病原体之间可能有所不同。在表征给定杀菌剂时，这一点值得考虑。